| 摘要 |
<p>PURPOSE:To prevent cam change-over during valve lift without use of a specific change-over timing controller and enhance fuel consumption performance and output performance by conducting change-over according to the operating condition. CONSTITUTION:In a high-low speed change-over mechanism in which a piston 19 is moved on cam shafts 11, 12 with hydraulic force or a return spring 22 to move a cam 26 with cam surfaces 31, 35, moving force of the piston 19 by the hydraulic force or the return spring 22 is set smaller than force to open valves 5, 7. Even if a moving force to the piston 19 is applied during valve lift, the piston 19 actually does not move and is not changed over. A sub-intake cam applying this change-over mechanism is mounted to a main intake cam 23, and the closing timing of a suction valve 5 is delayed to return a mixed gas within a cylinder to a suction port.</p> |
